Quantitative assessment of graves’ ophthalmopathy activity using 99mTc-DTPA SPECT/CT orbital imaging: a feasibility study with multiple indicators

In summary, this study confirms that quantitative indices from orbital ^99mTc-DTPA SPECT/CT, particularly SUV_mean-3D, effectively quantify EOMs inflammatory activity in GO. Parameters derived using CT-based 3D VOI delineation (SUV_mean-3D and SUV_max-3D) demonstrated superior reliability over traditional methods. Among all indices, SUV_mean-3D demonstrated superior diagnostic efficacy (AUC = 0.887) for differentiating active from inactive disease. These indices provide an objective tool for quantifying GO severity and monitoring disease changes during patient follow-up. This capability is vital for monitoring treatment response, guiding therapeutic decisions, and serving as a potential endpoint in clinical trials.